diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index d564bda7987..b1770920f06 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2800,6 +2800,10 @@ SDValue DAGCombiner::visitSUBSAT(SDNode *N) { if (N0.isUndef() || N1.isUndef()) return DAG.getConstant(0, DL, VT); + // fold (sub_sat x, x) -> 0 + if (N0 == N1) + return DAG.getConstant(0, DL, VT); + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && DAG.isConstantIntBuildVectorOrConstantInt(N1)) { // fold (sub_sat c1, c2) -> c3 |
